Knackered my Trotec Speedy 300 lens!

[Mark Ward]

Managed to completely knacker my lens up by cutting some cardboard for 2 minutes yesterday, black mark burnt into the middle of the lens that won't shift and has stopped the laser working properly
Used the Trotec settings for Cardboard too (first time ever) in the Job Control so well and truely off as I just can't understand how or why it has caused this damage!

Anyway, quote for a replacement 2,0" lens is £245.94 including the postage ($406)

I was thinking it would be nearer to £100. Very expensive this!

[Dan Hintz]

Used the Trotec settings for Cardboard too (first time ever) in the Job Control so well and truely off as I just can't understand how or why it has caused this damage!

Was air assist on and did you have good extraction flow? The settings alone won't cause a scarred lens, the lens had to be collecting soot.

[Mark Ward]

Was air assist on and did you have good extraction flow? The settings alone won't cause a scarred lens, the lens had to be collecting soot.

Have just looked and the default in JobControl for cardboard is Air Assist off
I genuinely didn't even think to look at this as we've not done cardboard before and it was a very quick one off job so took faith that Trotec would have set a safe set of defaults for it. Ultimately I know it is my machine and me that set the job to go, I just genuinely didn't think the default settings for a one off 2-3 minute job on cardboard could be so damaging!
Extraction flow was very good.
Live and learn!

[Scott Shepherd]

it was a very quick one off job so took faith that Trotec would have set a safe set of defaults for it.

The settings were right, it cut just fine. The problem is you had the nose cone on and the air off. There's no way for the software to know if you forgot to take the nosecone off. When you leave it on with the air off, it creates a vacuum and sucks the debris right into the lens.

[Jason Hilton]

Is there ever a good reason to not use air assist when cutting? I know when I was using epilog at the makerspace I'd turn it off when doing certain engraving, but I'd think that any cutting job would benefit from air assist?

[Mike Troncalli]

I don't know if I have ever NOT turned my air assist on. I have my Water pump, air assist and exhaust fan hooked up to a switched power strip. It is just old habit for me to hit switch 1 "Water Flow" first and then right before starting the job I hit switch 2 and 3... I have them in this order so that I can first "hear" the water pump (I don't have a visual flow window). Then I hit switch 2 so that I can hear the air assist compressor, after that switch 3 which is the exhaust (it is of course the loudest)..

[Bill George]

Its a glass lens, correct? With some carbon burnt on it, I can't believe that it can't be cleaned off with some solvent and re-used. No scrubbing just soft cloth. Even soaking in soapy water would soften I would think.

[Mark Ward]

The settings were right, it cut just fine. The problem is you had the nose cone on and the air off. There's no way for the software to know if you forgot to take the nosecone off. When you leave it on with the air off, it creates a vacuum and sucks the debris right into the lens.

That is the problem. I always leave the nose cone on and always have the air assist on for all the jobs I've done, however, I just presumed (wrongly) that the trotec settings would by default have the air assist on with the cardboard as it is the only time I've used that setting (I didn't check foolishly) for the cut which unfortnately they didn't, my fault for quickly rushing and not checking but it didn't even cross my mind

Its a glass lens, correct? With some carbon burnt on it, I can't believe that it can't be cleaned off with some solvent and re-used. No scrubbing just soft cloth. Even soaking in soapy water would soften I would think.

I've left the solution soaking in it and it won't shift, even picking with my nail doesn't budge any of it. Will post a picture up later.

[Bill George]

Wonder if an Ultra Sonic cleaner would work and not damage the lens?

[Kev Williams]

Soak the lens in oven cleaner, if that doesn't work nothing will. And it shouldn't hurt the lens itself.

[Paul Phillips]

I feel your pain Mark, I had to learn the hard way also, this has been discussed many times on this forum, new users take care! Steve has the right idea, air on, cone-on, air off, cone-off! REMEMBER THIS RULE!
http://www.sawmillcreek.org/showthre...acked+lens+uls

[Jiten Patel]

Mark, read this post http://www.sawmillcreek.org/showthre...y-lens-already

I did the same thing, probably a built up on the lens already. I did it cutting MDF and by default, air assist is off when you create a new profile in job control. I managed to get it off with about 30-40 minutes of gentle scrubbing - treat it like a woman and if should come off - nice and gentle and lots of patience!!!!

[Dan Hintz]

Its a glass lens, correct? With some carbon burnt on it, I can't believe that it can't be cleaned off with some solvent and re-used. No scrubbing just soft cloth. Even soaking in soapy water would soften I would think.

Zinc Selenide, but you can very quickly destroy the AR coating on it with scrubbing. You can't treat these lenses (or mirrors) like a piece of glass in your house's storm door.

Soak the lens in oven cleaner, if that doesn't work nothing will. And it shouldn't hurt the lens itself.

Gees, really, Kev? Oven cleaner? That'll strip the AR coating off in a heartbeat.

[Bob A Miller]

Mark, I too feel your pain... I just screwed up two of them last week... Obviously I tried a few things the second time around but the recommendation didn't work... I have gone to a 2.5" lens & rebuilding my air system. To compound things when I did have it up & running the job control software would stop in the middle of a job. Finally caught it saying "internal application error". Trotec technical support told me older laptops running the 15' supplied USB cable can have a voltage drop off that is enough to do that. So now have a 10' cable.

So I have been reading the cleaning ideas & will report back on that, now having ample opportunity to practice. Just not sure about giving the oven cleaner a try. Going to start I think with simple green. That works as a gentle organic paint remover.

Cheer up you aren't in this alone. For the record the replacement 2" lens was 410 can$ after tax.

[Keith Colson]

One great stain removing method is to simmer the lens in glycol (green anti freeze) in a pot on an outdoor stove for about 24 hours. If that does not work then the last thing you can do is polish the lens with some glass polish. This takes a layer of glass off and will leave you with imperfect focus but probably good enough for a lot of jobs. Either way you go, your lens coating is prolly stuffed.

My air assist is always on and the machine will not run if it's off. The only thing I do is turn down the pressure when doing metal engraving. It may not be the best thing to do but I do think it is the safest thing as I am bound to forget otherwise.

Good Luck
Keith